Search PubMed⌕ Search

Biomedical subjects

J S Roberts

Publications and source records attributed to J S Roberts.

At least 55 records · Page 3Linked to original sources
PubMed1988

Extent of DNR policies varies across healthcare settings.

A cross-section random survey of acute care hospitals, psychiatric hospitals, long-term care facilities, and hospices was conducted in 1986 to determine the extent of use, the nature, and the implementation of do-not-resuscitate (DNR) policies. Data also were collected to identify the common problems of implementing DNR policies, as well as how conflicts in the use of DNR orders are resolved. The survey found that 30.7 percent of healthcare organizations have a formal policy, 28 percent have an informal policy, and 41.3 percent have no policy. Formal policies were found in 56.9 percent of acute care and 42.9 percent of hospice care settings, compared with 11.4 percent in psychiatric and 20.1 percent in long-term care settings. Although predictors varied across the four settings studied, formal policies were associated with larger organizations, the use of consultation, accreditation by the Joint Commission on Accreditation of Healthcare Organizations, and the presence of an ethics committee. The recognition of a living will plays a small role in the presence of a formal DNR policy. Given the growing concern of the American public and healthcare organizations over DNR orders, the implications of this study call for careful attention to DNR and related medical and ethical issues and the establishment of policies that clearly delineate when, how, and with whom such issues are discussed and resolved.

Cross-Sectional Studies↗
PubMed1987

Reviewing the quality of care: priorities for improvement.

Rapid and substantial change in our health care system has prompted careful analysis of the quality of health care and the effectiveness of the methods used to review and improve quality. Although welcome, those applying this scrutiny must recognized that improvement in the quality of health care will take the concerted and cooperative efforts of health policymakers, health care practitioners, health care organizations, consumers of care, purchasers of care, and those organizations that define the state of the art and monitor the quality of care. Particular attention should be devoted to: Gaining a common understanding of the definition of high quality care. Utilizing review programs that are continuous, priority-oriented, and effective. Assuring that the indicators and criteria used in monitoring care are consistent with the practical state of the art. Recognizing the importance of and improving the effectiveness of peer review. Investing in improved diffusion of current clinical knowledge to practitioners. Being properly circumspect about how one best achieves improvement in areas of substandard care.

Evaluation Studies as Topic↗
PubMed1985

Effect of energy intake on the promotion of mammary carcinogenesis by dietary fat.

The effect of low-fat and high-fat diets on the induction of mammary carcinomas by 1-methyl-1-nitrosourea (MNU) was studied in female Sprague-Dawley rats. All rats were given MNU (25 mg/kg body wt) at 50 days of age. For the first 17 weeks after carcinogen administration, they were fed a purified diet containing either 5 or 20% fat incorporated into agar gel. Food intake was restricted, so that the amounts fed provided the same amount of net utilizable energy each day for both groups, regardless of the fat content of the diets. From 17 to 32 weeks, the diets were fed ad libitum. During the restricted feeding period, there was no significant difference in tumor incidence or in the number of tumors detected between the groups. During the weeks in which animals were fed ad libitum, significantly more tumors appeared in the high-fat group than in the low-fat group. The data provide support for the hypothesis that consumption of a high-fat diet can lead to an enhancement of mammary carcinogenesis. It appears, however, that diets must be consumed ad libitum for the stimulatory effect on tumor occurrence to be exhibited.

Animals↗
PubMed1982

Effects of early cold adaptation on food efficiency and dietary-induced thermogenesis in the adult rat.

The food intakes of male and female rats (Harvard strain) adapted to cold (5 degrees C) starting at weaning were studied in the cold and during reacclimation to 25 degrees C. Following 24 hr food deprivation, the male rats regained the weight they had lost without making up for the food they had missed (increased food efficiency), while the female rats ate 75% more food than they had missed in regaining their body weights (decreased food efficiency), independent of the temperature at which the animals were housed. On a high fat diet, both cold groups gained less weight than did the two control groups. However, each female group gained significantly less weight than its same temperature male group. Dietary-induced thermogenesis was significantly enhanced in male cold adapted rats 3 months after reacclimation to the zone of thermal neutrality but not in cold adapted female rats. Sex and strain differences are discussed. These data indicate that early chronic cold exposure results in both immediate and long-term changes in food efficiency and metabolism in adult rats, but the effects vary with the sex of the animal.

Acclimatization↗
PubMed1978

Oxytocin-stimulated production of prostaglandin F2alpha by isolated endometrium of rabbit: modulation by ovarian steroids.

To test the hypothesis that ovarian steroid hormones modulate oxytocin-induced release of prostaglandin F2alpha (PGF2alpha) from uterine endometrium, 2 ovariectomized rabbits were pretreated with progesterone (5 mg/day for 10 days), 2 with estradiol-17 beta (25 microgram/day for 10 days), 2 with both steroids, and one with sesame oil only. On the last day of treatment, endometrial fragments were excised and incubated in vitro with or without oxytocin (100 muU/ml). Although endometrium from rabbits pretreated with combined steroids released more PGF2alpha immediately after excision than did tissue from animals pretreated with either steroid by itself, endometrium from animals pretreated with estradiol-17 beta alone released the most PGF2alpha during sustained incubation in vitro. Moreover, only this tissue exhibited significant oxytocin-dependent release of PGF2alpha. At the dosages used, progesterone completely antagonized both of these effects of estradiol-17 beta. The results support the hypothesis that ovarian steroid hormones regulate oxytocin-dependent release of PGF2alpha from endometrial cells. A posible mechanism of action is suggested.

Animals↗
PubMed1978

Eye care delivery in prepaid group practice.

This paper represents original research from the clinical implementation over a five-year period of eye care as a primary health care resource within the Medical Group of the Genesee Valley Group Health Association at the Joseph C. Wilson Health Center in Rochester, New York. The primary care delivered at this health maintenance organization has been organized in a multidisciplinary fashion with the doctor of optometry functioning as the primary eye care provider, and clinical administrator, and the ophthalmologist functioning as the medical and surgical consultative specialist. The data and information generated from this research represents four years of extensive clinical care delivered to a prepaid patient population in excess of 35,000 members.

Adolescent↗
PubMed1976

Oxytocin-stimulated release of prostaglandin F2alpha from ovine endometrium in vitro: correlation with estrous cycle and oxytocin-receptor binding.

Endometrial and myometrial tissues, obtained from Merino ewes on 5 different days of the estrous cycle, were incubated at 37 C in 30 ml of gassed (95% O2:5% CO2) Krebs-bicarbonate buffer containing, 0, 10, 100 or 1,000 muU/ml oxytocin. Aliquots of the medium were removed at 10 min intervals and examined for prostaglandin F2alpha (PGF2alpha) content by radioimmunoassay. Fresh-frozen (-70 C) samples of endometrial and myometrial tissue were homogenized in Tyrode's solution. Particulate fractions from each tissue, sedimenting between 1,000 X g for 10 min and 165,000 X g for 30 min, were prepared and assayed for [3H]oxytocin-binding activity. Endometrium incubated in vitro released PGF2alpha spontaneously and oxytocin enhanced this release in a dose-dependent manner. The degree of enhancement with low doses of oxytocin appeared to increase as estrus approached, reaching a maximum on the day of estrus. High-affinity binding sites (Kd = 5 to 7 X 10(-10) M) were found in both myometrium and endometrium. The number of high-affinity sites rose to a peak at estrus in both tissues but the binding capacity of endometrium was twice that of the myometrium at this time. Although both tissues released PGF2alpha during incubation, oxytocin enhanced release from endometrial tissue only. The results suggest that (i) the endometrium is a target for oxytocin, (ii) synthesis of PGF2alpha by the uterus may involve interaction between oxytocin and its endometrial receptors and (iii) ovarian steroids may influence uterine PG synthesis by regulating the availability of these receptors.

Animals↗
PubMed1976

Prostaglandin F2alpha production by the brain and its role in LH secretion.

The arteriovenous difference in the concentration of prostaglandin F2alpha (PGF2alpha) across the brain of the anestrous sheep was measured before and during the induction of luteinizing hormone (LH) secretion with estradiol-17beta (E2-17beta). The results indicate that (a) the brain is a significant source of PGF2alpha, (b) the release of PGF2alpha from the brain occurs in pulses with a circhoral rhythm, and (c) the process through which estrogen exerts its negative and positive feedback effects on LH secretion may depend upon amplitude modulation of PGF2alpha output from the brain.

Animals↗
PubMed1975

Prostaglandin F2alpha production by the brain during estrogen-induced secretion of luteinizing hormone.

The arteriovenous difference in the concentration of prostaglandin F2alpha (PGF2alpha) across the brain of the anestrous sheep was measured before and during the induction of luteinizing hormone secretion with 17 beta-estradiol. The results indicate that (i) the brain in vivo is a significant source of PGF2alpha, (ii) the release of PGF2alpha from the brain occurs in pulses with a circhoral rhythm, and (iii) the process through which estrogen exerts its negative and positive feedback effects on luteinizing hormone secretion may involve amplitude modulation of PGF2alpha output from the brain.

Animals↗